Is The Last of Us 2 in Development at Naughty Dog?

Naughty Dog is allegedly working on The Last of Us 2, despite the fact that the first game remains ongoing, as well as the recent announcement of Uncharted for PS4. Releasing in 2015, according to Omelete, The Last of Us 2 is already in production for PlayStation 4.

Given the studio's release patterns, a Last of Us sequel next year
doesn't make sense, so take the rumor with a grain of salt. Naughty Dog
is still scheduled to release The Last of Us' expansion on February 14,
while many other developers toil away on the next Uncharted. This leaves
few resources for a sequel to The Last of Us, on new hardware no less.
Furthermore, given development cycles, it's unlikely that a project such
as this would be out of pre-production and in full development.